There are conflicting design needs in improving performance of HAMR heads. There is a design need for a fast access time which requires enhanced control characteristics such as high speed, low overshoot positioning speed during seeking, and precise position controllability (during tracking) with a low expenditure of electrical power for position control in both modes. Enhanced control characteristics drive a design toward reducing moving mass and reducing mechanical and aerodynamic drag on the HAMR head and its suspension.
There is a design need to deliver high levels of optical radiation to the HAMR head in order to provide rapid heating of magnetic media. Various known solutions for coupling high levels of optical radiation to the HAMR head lead to arrangements that adversely affect control characteristics.
Increased mass and aerodynamic drag due to large optical source structures mounted on the HAMR head and/or head suspension and pivoting arm slow down movement of the HAMR head and lead to either increased access time or unacceptably high electrical power consumption for position control. In addition, some optical source structures that are mounted to HAMR heads can overheat magnetic reading or writing components on the head.
When optical source structures are remotely mounted in a non-moving location, optical transmission media (such as lenses, mirrors or optical fibers) coupled between the optical source and the HAMR head add moving mass or a difficult-to-predict variable component of mechanical resistance to motion that leads to either increased access time or unacceptably high levels of electrical power consumption.
A HAMR arrangement is needed that will provide an enhanced combination of low power consumption, freedom from overheating of magnetic components and fast access time.
Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.